Lecture 6: Speciation Flashcards
Define ‘speciation’.
The formation of two evolutionary independent species from a single common ancestor.
What are the four types of speciation?
Allopatric, peripatric, parapatric and sympatric.
Define ‘allopatric speciation’.
A physical barrier divides a continuous population.
Define ‘peripatric speciation’.
A small founding population enters a new or isolated niche.
Define ‘parapatric speciation’.
A new niche found adjacent to the original niche.
Define ‘sympatric speciation’.
Speciation occurs without physical separation inside a continuous population.
Define ‘disruptive selection’.
When organisms prefer specific physical traits.
Name the different types of prezygotic barriers.
Habitat, temporal, behavioural, mechanical and gametic isolation.
Name the different types of post zygotic barriers.
Reduced hybrid viability, reduced hybrid fertility and hybrid breakdown.
What is Haldane’s Rule?
When in the F1 offspring of two different animal races one sex is absent, rare, or sterile, that sex is the heterozygous sex.
Define ‘gametic isolation’.
Female and male gametes fail to atttract eachother or are inviable.
Define ‘reduced hybrid viability’.
Hybrid zygotes fail to develop or fail to reach sexual maturity.
Define ‘reduced hybrid fertility’.
Hybrids fail to produce functional gametes.
Define ‘hybrid breakdown’.
Offspring of hybrids have reduced viability or fertility.
